I do not know what bookkeeping means in the context of internet connections. My assumption is that you plan to ride around in an RV while someone else is driving. As you ride along you would like to get your work done. Your internet connection needs do not likely require a VPN connection which means your experience may be more positive than negative with a VZW mobile broadband device.
Something you need to think about is if you plan to be in motion while accessing the internet or not. Traveling and connecting to local VZW towers may not always be a pleasant experience. Towers will migrate you around from one to another causing you to refresh or reset whatever you were working on from time to time. The tower handoffs are much more obvious when VPN connected as they are more sensitive to misc. network connection events. If you are sitting in an RV park you may have better luck, but then again you will be fighting with your neighbors for VZW spectrum.
Then you need to think if this is a personal internet connection or something you want to share with other network devices. For example a Jetpack is like a small home router that can support multiple wireless connections. However Jetpacks are not intended to be powered on and used 24/7 like your home router. Since this is an RV and normal power should be available you can consider a 4G LTE home router instead of a Jetpack for a 24/7 connection scenario.
Otherwise if you only want to connect a single laptop to the internet then you can consider a USB modem. USB modems plug directly into your laptop and generally perform better than Jetpacks and 4G LTE routers because there is no additional Ethernet cable or WiFi connection between the modem and your laptop. The problem with USB modems is that you need hardware drivers and software to operate them so you need a compatible OS or a home router with a USB modem port to enable them. Oh, and USB modems tend to bust off a lot since they are directly connected and sticking out of the side of the laptop.